The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon ...The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon Gold Mine). Dormant since 1998, Mapping Services of most of the West African countries hardly provide geological maps at the scales of: 1/200,000, 1/50,000 and 1/25,000. This situation of unavailability of detailed geological maps does not help mining operators in the selection of prolific areas and also in the interpretation of in soil geochem anomies or gold mineralizations. Consequently, during the years 2020 and 2021, we have undertaken a campaign of geological mapping and petro-structural study of the northern sector of Komborodougou, located in the southern extension of Banfora Birimian Belt. This work, which allowed the realization of a geological map at 1/20,000 scale, reveals that: the mapped area includes three (3) major lithological units: 1) a volcano-sedimentary unit made up of metasediments (metaarenites, metasiltites and metaflyschs) and metavolcanites (metabasalts), which are metamorphosed and outcrop in the form of schists;2) a metaplutonic and intrusive unit composed on the one hand of quartz-diorites and metagabbros, and on the other hand of granites and granodiorites;3) and finally, a unit of dikes formed by microgranites, microgabbros, aplites and quartzites. The volcano-sedimentary complex is affected by a regional fold with an axis subparallel to the regional tectonic grain and an S1 schistosity oriented NE-SW to NNE-SSW with steep dips (>60o), except for those of the metaflyschs which are weak (o);a regional NW-SE compression would be at the origin of the setting of this schistosity. The volcano-sediment and metaplutonite complex is crossed in a NNE-SSW direction by a senetral shear-zone or main shear-zone and secondary shear-zones oriented sometimes NE-SW or N-S. These shear-zones are intersected by more or less dextral or senestral strike-slip faults of NW-SE and E-W trends. N-S to NNE-SSW (N0o - N20o) and NW-SE (N130o - N160o) vein systems associated with the various shear-zones are the hosts of the gold mineralization in the region. These veins have been mined by orpaillors for more than two decades. The northern sector of Komborodougou is in the NNE continuity of the gold mineralization highlighted by the mining company Mako Gold Sarl on its Gogbala and Tchaga prospects, Napie project.展开更多
Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the on...Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the one hand on the gravimetric geophysical method and on the other hand, on petro-structural studies. The geophysical results highlighted two gravimetric facies characterized respectively by high density (ΔBg > 121 mGal) and low density (ΔBg < 114 mGal) anomalies. From a lithological point of view, the denser domains are made up of intrusive rocks dominated by granodiorites and tonalites cutting low density facies composed of Tarkwaian formations (polygenic conglomerates and arkosic sandstones) and volcanics (tuffs and cinerites). Structurally, these different lithological groups are affected by brittle (fractures, faults, strike-slip) and ductile (folds, schistosities and mineral lineations) deformations. These structures are mainly oriented NNW-SSW, WNW-ESE and NE-SW. The description of the sulphide minerals reveals a style of gold mineralization of the Tarkwaian formations.展开更多
The semi-industrial permit of Koffissiokaha, south-eastern area of Katiola, is located in the northern part of Fêtêkro Birimian Greenstone Belt (Côte d’Ivoire). This permit, applicated by the comp...The semi-industrial permit of Koffissiokaha, south-eastern area of Katiola, is located in the northern part of Fêtêkro Birimian Greenstone Belt (Côte d’Ivoire). This permit, applicated by the company Blue-Hill Exploration Sarl (BHEX), is in the southern continuity area of Lafigué permit (Endeavour Mining). Blue-Hill will have to work to highlight potential gold mineralization, quantify it (resource calculation) and initiate administrative procedures to obtain a Semi-Industrial Exploitation Authorization (AESI). Our recent works, including field mapping coupled with petrographic and microstructural studies, are therefore intended to contribute to the knowledge of the geology and to the evaluation of the gold potential of this permit. They suggest that Koffissiokaha permit includes four major lithologic units: 1) a sedimentary unit formed by metaarenites and metasiltites, 2) a unit of mafic pyroclastites (cinerites, tuffs and volcanic breccias) 3) a plutonic unit of metagabbro and finally, 4) a lode-type unit made up of metarhyodacites. The metamorphism that affected the volcano-sedimentary rocks is of low grade to greenschist facies. On the structural level, deformations with variable gradients are noted. The major planary structure, the schistosity, is oriented N20 - 40 with weak (°), moderate (50°- 60°) and steep dips (>70°) or subvertical. The faults generally correspond to narrow dextral or senestral shear-zones (75°) towards south-east or subvertical. They are most often intersected by late strike-slip faults-oriented NW-SE, NNW-SSE and N-S. Quartz veins are associated with faults or deformation zones. They are generally oriented N20 to N40, with weak (°), moderate (55°- 65°) and steep dips (>75°). Orientations of joints and fractures are mostly subparallel to the plans of schistosity, shears and most of quartz veins. However, ENE, WNW and N-S fractures are also distinguished. The sulphide paragenesis consists of pyrites (and pyrrhotites), arsenopyrites and chalcopyrites. Gold mineralization is controlled by both structural and hydrothermal parameters.展开更多
This study aims to contribute to improve knowledge on geological formations of Comoé basin. The petrographic study of the geological formations of Koun Fao has highlighted two major lithological families: magmati...This study aims to contribute to improve knowledge on geological formations of Comoé basin. The petrographic study of the geological formations of Koun Fao has highlighted two major lithological families: magmatic rocks consisting of monzonites, monzogranites, diorites, biotite granodiorites, syenites, porphyritic micromonzonites and porphyritic dacite and metamorphic rocks from sedimentary origin (quartz schists, meta-greywackes, schists, andalusite chloritoschist and paragneiss). These formations are affected by amphibolite to greenschist facies metamorphism and hydrothermal alteration (pervasive and vein) marked by the presence of quartz, epidotes, chlorites and sericite. Minerals such as andalusite, muscovite and chlorite characterize a local low pressure contact metamorphism in the andalusite chloritoschist. Remote sensing data (Landsat 8 image) coupled with field data allowed the production of a geological map of the area. The study of the structures and microstructures highlighted two deformation mechanisms. These are flattening and simple shear (ductile and brittle). The study area is affected by four deformation phases: D1 marked by a N-S to NNE-SSW elongation, D2 marked by a NW-SE to NNW-SSE compression phase, D3 which is a NE-SW to NNE-SSW transpression phase and D4, responsible for late structures, marked by a NW-SE to NNW-SSE transpression phase.展开更多
Mount Fouimba and Mount Goma (Seguela) greenstone belts petro-structural studies combine remote sensing, geophysics, petrography and structural analysis. In view of establishing mapping details of paleoproterozoic geo...Mount Fouimba and Mount Goma (Seguela) greenstone belts petro-structural studies combine remote sensing, geophysics, petrography and structural analysis. In view of establishing mapping details of paleoproterozoic geological formations, geological setting rocks observed are essentially magmatic formations, such as two-mica granite, granodiorites, and porphyritic basalts;and a few metamorphics which are metatonalite, amphibolites and amphibo-lopyroxenites. Remote sensing, such as Landsat 8 OLI satellite imagery and geophysical data, has been combined to show regional NNE-SW shear zone. Tectonic structures and microstructures have enabled to identify two main deformation phases: D1 phase corresponding to compression, and D2 is a transpression phase. Mechanisms responsible for deformations are respectively flattening and transpression. Geological formations derived from mantle origin but contain crustal components, and their tectonic setting occurred during subduction.展开更多
文摘The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon Gold Mine). Dormant since 1998, Mapping Services of most of the West African countries hardly provide geological maps at the scales of: 1/200,000, 1/50,000 and 1/25,000. This situation of unavailability of detailed geological maps does not help mining operators in the selection of prolific areas and also in the interpretation of in soil geochem anomies or gold mineralizations. Consequently, during the years 2020 and 2021, we have undertaken a campaign of geological mapping and petro-structural study of the northern sector of Komborodougou, located in the southern extension of Banfora Birimian Belt. This work, which allowed the realization of a geological map at 1/20,000 scale, reveals that: the mapped area includes three (3) major lithological units: 1) a volcano-sedimentary unit made up of metasediments (metaarenites, metasiltites and metaflyschs) and metavolcanites (metabasalts), which are metamorphosed and outcrop in the form of schists;2) a metaplutonic and intrusive unit composed on the one hand of quartz-diorites and metagabbros, and on the other hand of granites and granodiorites;3) and finally, a unit of dikes formed by microgranites, microgabbros, aplites and quartzites. The volcano-sedimentary complex is affected by a regional fold with an axis subparallel to the regional tectonic grain and an S1 schistosity oriented NE-SW to NNE-SSW with steep dips (>60o), except for those of the metaflyschs which are weak (o);a regional NW-SE compression would be at the origin of the setting of this schistosity. The volcano-sediment and metaplutonite complex is crossed in a NNE-SSW direction by a senetral shear-zone or main shear-zone and secondary shear-zones oriented sometimes NE-SW or N-S. These shear-zones are intersected by more or less dextral or senestral strike-slip faults of NW-SE and E-W trends. N-S to NNE-SSW (N0o - N20o) and NW-SE (N130o - N160o) vein systems associated with the various shear-zones are the hosts of the gold mineralization in the region. These veins have been mined by orpaillors for more than two decades. The northern sector of Komborodougou is in the NNE continuity of the gold mineralization highlighted by the mining company Mako Gold Sarl on its Gogbala and Tchaga prospects, Napie project.
文摘Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the one hand on the gravimetric geophysical method and on the other hand, on petro-structural studies. The geophysical results highlighted two gravimetric facies characterized respectively by high density (ΔBg > 121 mGal) and low density (ΔBg < 114 mGal) anomalies. From a lithological point of view, the denser domains are made up of intrusive rocks dominated by granodiorites and tonalites cutting low density facies composed of Tarkwaian formations (polygenic conglomerates and arkosic sandstones) and volcanics (tuffs and cinerites). Structurally, these different lithological groups are affected by brittle (fractures, faults, strike-slip) and ductile (folds, schistosities and mineral lineations) deformations. These structures are mainly oriented NNW-SSW, WNW-ESE and NE-SW. The description of the sulphide minerals reveals a style of gold mineralization of the Tarkwaian formations.
文摘The semi-industrial permit of Koffissiokaha, south-eastern area of Katiola, is located in the northern part of Fêtêkro Birimian Greenstone Belt (Côte d’Ivoire). This permit, applicated by the company Blue-Hill Exploration Sarl (BHEX), is in the southern continuity area of Lafigué permit (Endeavour Mining). Blue-Hill will have to work to highlight potential gold mineralization, quantify it (resource calculation) and initiate administrative procedures to obtain a Semi-Industrial Exploitation Authorization (AESI). Our recent works, including field mapping coupled with petrographic and microstructural studies, are therefore intended to contribute to the knowledge of the geology and to the evaluation of the gold potential of this permit. They suggest that Koffissiokaha permit includes four major lithologic units: 1) a sedimentary unit formed by metaarenites and metasiltites, 2) a unit of mafic pyroclastites (cinerites, tuffs and volcanic breccias) 3) a plutonic unit of metagabbro and finally, 4) a lode-type unit made up of metarhyodacites. The metamorphism that affected the volcano-sedimentary rocks is of low grade to greenschist facies. On the structural level, deformations with variable gradients are noted. The major planary structure, the schistosity, is oriented N20 - 40 with weak (°), moderate (50°- 60°) and steep dips (>70°) or subvertical. The faults generally correspond to narrow dextral or senestral shear-zones (75°) towards south-east or subvertical. They are most often intersected by late strike-slip faults-oriented NW-SE, NNW-SSE and N-S. Quartz veins are associated with faults or deformation zones. They are generally oriented N20 to N40, with weak (°), moderate (55°- 65°) and steep dips (>75°). Orientations of joints and fractures are mostly subparallel to the plans of schistosity, shears and most of quartz veins. However, ENE, WNW and N-S fractures are also distinguished. The sulphide paragenesis consists of pyrites (and pyrrhotites), arsenopyrites and chalcopyrites. Gold mineralization is controlled by both structural and hydrothermal parameters.
文摘This study aims to contribute to improve knowledge on geological formations of Comoé basin. The petrographic study of the geological formations of Koun Fao has highlighted two major lithological families: magmatic rocks consisting of monzonites, monzogranites, diorites, biotite granodiorites, syenites, porphyritic micromonzonites and porphyritic dacite and metamorphic rocks from sedimentary origin (quartz schists, meta-greywackes, schists, andalusite chloritoschist and paragneiss). These formations are affected by amphibolite to greenschist facies metamorphism and hydrothermal alteration (pervasive and vein) marked by the presence of quartz, epidotes, chlorites and sericite. Minerals such as andalusite, muscovite and chlorite characterize a local low pressure contact metamorphism in the andalusite chloritoschist. Remote sensing data (Landsat 8 image) coupled with field data allowed the production of a geological map of the area. The study of the structures and microstructures highlighted two deformation mechanisms. These are flattening and simple shear (ductile and brittle). The study area is affected by four deformation phases: D1 marked by a N-S to NNE-SSW elongation, D2 marked by a NW-SE to NNW-SSE compression phase, D3 which is a NE-SW to NNE-SSW transpression phase and D4, responsible for late structures, marked by a NW-SE to NNW-SSE transpression phase.
文摘Mount Fouimba and Mount Goma (Seguela) greenstone belts petro-structural studies combine remote sensing, geophysics, petrography and structural analysis. In view of establishing mapping details of paleoproterozoic geological formations, geological setting rocks observed are essentially magmatic formations, such as two-mica granite, granodiorites, and porphyritic basalts;and a few metamorphics which are metatonalite, amphibolites and amphibo-lopyroxenites. Remote sensing, such as Landsat 8 OLI satellite imagery and geophysical data, has been combined to show regional NNE-SW shear zone. Tectonic structures and microstructures have enabled to identify two main deformation phases: D1 phase corresponding to compression, and D2 is a transpression phase. Mechanisms responsible for deformations are respectively flattening and transpression. Geological formations derived from mantle origin but contain crustal components, and their tectonic setting occurred during subduction.
